Hygrometer.



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HYGRon/IETER'.y A'PPLlcATloNTlLEn SEPT. e, 1914.

Patented Mar. 21, 1916. l

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WILLIAM H. BRISTOL, OIE' WATERBURY, CONNECTICUT, 'ASSIGNOR T0 THE BRISTOL" COMPANY, 0F WATERBURY, CONNECTICUT, A CORPORATION OF CONNECTICUT.

HYGROMETER.

specification nf-Letters Patent. iptented Mam 21, 19160 Application led September 8', 1914. Serial No. 860,771.

To all whom t may concern.'

Be it known that I, WILLIAM H. BRISTOL, a citizen of the United States, and a resident of Waterbury, in the county of New Haven Aand State of Connecticut, have invented cer tain new and useful Improvements in I-Iygrometers, of which the following is a specification.

The invention relates to vhygrometers, more particularly to hygrometers of the. wet and dry bulb thermometer type wherein the humidity is measured by the cooling effect ofthe evaporative Apower of the atmosphere `at different temperatures and different percentages of saturation. In hygrometers of this type, the wet bulb member is generally covered with absorbent material'adapted to be suitably moisten'ed; but, owing to the fact that the fibers of the material become coated with dust and dirt and the pores of the material filled therewith so that said material is no longer hygroscopic, frequent change of the covering is necessary, for the instrument, otherwise, would indicate in an erratic and grossly inaccurate manner.

, It 'is the object of the present invention toavoid the necessity ofsuch change or renewal of the covering and to provide a hygrometer which may operate for considerable periods of time without impairment of the accuracy of its indications.

A further object of the invention is to prevent matter which may have gone into solution from depositing on said wet bulb during evaporation.

The nature of the invention will be best understood when described in connection with the accompanying drawings,.in which- Figure 1 is a diagrammatic view illustrat.

ing the improved hygrometer installed in a Fig. 2 is a plan of thedry kiln or the like. wet and dry bulbs of the hygrometer and Fig. 4 is a cross-section taken on tlieyline li-4, Fig. 2.

' Similar characters of reference designate corresponding parts'throughout the several VIEWS.

Fig. 3 is an end view of distance from the point where the humidity 8 are inserted, 'as shown. Thesel bulbs are mounted in a suitable supporting frame work 12 and to the upper vend of which i's secured a easing 13 affording a water supplychamber which is in communication through a supply pipe 14 with a suitable tank 15 containing the water. From this tank, the Wa# ter is automatically fed4 to the said chamber as required, the level of water in the latter being maintained constant as is well understood. A strip or cloth or textile fabric 16, providing a suitable covering or wickfor thewet bulb, extends from casing 13 and is arranged to substantially cover'the surface of said bulb and from which it extends downwardly below the level of the water in casing 13 and, preferably, also below'said bulb. The lower end is placed in a casing 17 attached to the underside of the frame 12 and forming a chamber or receptacle for the surplus water from said-wet bulb covering. An overflow .pipe 18 communicates with the interior ofsaid casing 17 to remove the surplus water therefrom andeXtendS beyond the kiln 11, its outlet being at the proper height to maintain the desired level of the Water in the casing 17. A siphon action is thereby afforded and by means of which the water is continuously and progressively supplied to said cover or wick 16 from the casing 13 and delivered into the casing 17, from whence the surplus is removed as here-` inbefore described. This will effect the removal of any dirt or dust from the covering, and which would otherwise settle thereon and impair the reliability of the instrument, and will carry along, also, any matter which might go into solution and tend to deposit on thebulb during evaporation. i The cover will, therefore, render satisfactory service for long periods of time without necessitating renewal or the use of mechanical devices lfor advancing or cleaning the same.

I claim \1. In a. hvgrometer: a wick member; a

casing providing a water supply chamber Water supply chamber. and in contact with said wick, which latter has a portion extending voutside said casing and its end below thev level of the Water therein and extending beyond the seid Wet bulb member.

2. In .a hvgrometer: :t Wick member; a casing providing a Water supply chamber into which one end of said Wick member dips; and a Wet bulb member located outside of Seid casing below the level of Water therein and in contact with the outer portion of Said Wick` the end of which extends below the level of the Water .and said Wet bulb member.' A f 3. In a hvgrometerz a wick member; a

casing providing afwater supply chamber into which one end of said Wick member dips.; and a Wet bulb member 4outsiderthe vater of said Water supply chamber and in Contact with said -wick. the other end of which extends outside said casingnnd below the level of the' Water therein. y

4. In a hvgrometer: a Wick member; a; easing providing aywater supply chamber into which one 'endofsa-id ,Wick member dps;and a wet bulb member outside the A dips; a second casing' located below the level of the water in said Water supplv chamber and `into which the other end of said Wick Water of said Water supplv chamber andin Contact With the outer portion ofv said Wick. 5. In 'a hygrometer: a Wick member a beyond the casingv providing a Water supply chamber 1 into Which one end of said Wick member dips; a second casing located below the level `of the Water in said watersupplyY chamber and intowhich the other end of said'wick dips; a ,wet bulb memberoutside the Water of said r. ater supply chamber and -in contact with the outer portion of said Wick;l and an overflow ond casing.

6. In a h vgrometer: a wick member; a. casingproviding a Water supply chamber pipe from said vseclintoiwhich said Wick member dips; a wet bulb' member outside thewater of said Water supply chamber and in Contact withl 

